144 



THE ENTOMOLOGIST. 



changed throughout, thus giving rise to a very abrupt and vivid 

 contrast. 



(2) Twenty-eight days refrigerator, the perfect insects emerging 

 at the normal temperature 10 days afterwards. The butterflies, 

 33 per cent, of which were crippled, showed on the whole no diffe- 

 rence worth speaking of from the series just described. The 

 only noticeable point is that a small number were still darker 

 than the most extreme specimens of the previous series. 



9. Argynnis aglaia, L. 

 a. Warmth. 



Four days at 36° C. (97° F.), then 1—2 more days at the 

 normal temperature until the butterflies appeared. 



These show— in the female as well — a very light reddish- 

 brown ground colour on the upper surface, but no noteworthy 

 modification of the black markings. 



Again, on the under side the elements of the pattern are not 

 altered in outline ; nevertheless the greyish-green shades which 

 occur at the base of the wing and just internally to the silver 

 spots of the outer border are darker in tone, and stand out much 

 more conspicuously than in average specimens. 



h. Cold. 



(1) Twenty-eight days in the refrigerator, then 12 days at 

 the normal temperature until the butterflies appeared. Twenty- 

 one pupfe yielded only three perfect insects ; the remaining pupae 

 either perished or gave rise to crippled specimens. 



The reddish-brown ground colour is unaltered. The black 

 spots at the base of the fore wing increase in size ; not so, how- 

 ever, the series of spots lying further out, nor the markings of 

 the outer margin, nor again the pattern of the hind wing. On 

 the under side of the hind wing the greyish-green shades, which 

 I have already described in their place, take on a tinge of brown. 



(2) Forty-two days in the refrigerator, then 16 days at the 

 normal temperature. 



Of 12 pupae, 10 yielded no butterfly. The two that emerged 

 are both aberrant, and both in the same direction. 



Upper surface. — The reddish-brown ground colour becomes 

 duskier, and the basal spots are enlarged. The root of the wing 

 below the central cell is blackened. The series of spots which 

 lie further out begin on both pairs of wings to dwindle. The 

 spots lying in a curved series adjacent to the outer border of 

 both fore and hind wing are prolonged in a conical form inwards. 



Under surface. — The constituents of the pattern on the fore 

 wing become larger or smaller in correspondence with those on 

 the upper surface. 



On the hind wing the greyish green between the three silver 

 spots on the costal margin is darkened to a blackish brown ; in 



